The trick is very simple. All you have to do is just flick the wrist. It’s much more accurate than it seems- oh, wait, the cops are here. Hold on, I’m gonna shank em’. Be right back.
Eh... put too much effort on something that is so little. Giving some paper some knife edge and try to stab something.
Not saying it’s bad. No. But, try something a little bit simple but impactful.
A bullet is better than a rubber ball.